# File Size Converter vs UnderMB

The clearest difference is in-app purchases: UnderMB at none against File Size Converter's 3. UnderMB also leads on update cadence (every 11 days vs monthly) and device support (3 vs 1). File Size Converter's advantage is ads (none vs shown). On price there is nothing between them.

Both are free to download. File Size Converter sells 3 in-app purchases, starting at $2.99 per 7 days. UnderMB asks for nothing beyond the download.

File Size Converter ships an update monthly, UnderMB every 11 days. The most recent releases landed on October 28, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | File Size Converter | UnderMB |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/undermb-file-size-compressor/id6811049521/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | Monthly | **Every 11 days** |
| Size | 5 MB | 9 MB |
| Requires iOS | 17.0 | **15.0** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Phuc Pham](https://appshunter.io/developer/1893081423) | [CEMRE SIMSEK](https://appshunter.io/developer/6801148028) |

## What reviewers say

### File Size Converter

[App page](https://appshunter.io/ios/app/file-size-converter/id6772165773)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Binary Units · Weekly | $2.99 | per 7 days |
| Disk Capacity · Yearly | $14.99 | per year |
| Download Time · Pay Once | $29.99 | one-time |


### UnderMB

[App page](https://appshunter.io/ios/app/undermb-file-size-compressor/id6811049521)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is File Size Converter free?

File Size Converter is free to download, with in-app purchases available.

### Is UnderMB free?

UnderMB is free to download, with no in-app purchases.

### Do File Size Converter or UnderMB have ads?

UnderMB shows ads; File Size Converter does not.

### Which is updated more often, File Size Converter or UnderMB?

File Size Converter ships an update monthly, and UnderMB every 11 days. Most recently, File Size Converter was updated on October 28, 2026 and UnderMB on October 29, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*